Vertical grow: digital ballast

I am setting up a vertical growing room and wondering what digital ballast to buy. I am thinking about a 600, 750, or 1000 w light. Anyone have any feedback on: Lumatek, future bright, or galaxy? How far should I keep these plants away from the light?

keep the light far away at first, then move to about 18 inches. Depending on the amount of heat. I have a Lumatek so i cant speak to the other brands, but so far it has been dependable. It has some cool features like if there is an outage, it has a fuse to protect the ballast against a blow out, and it has a feature that waits 15 minutes after an outage and turns on automatically.

A cooltube could be used vertically (sans reflector) for close light placement.

Check out the DUAL 600 watt Lumatek ballast...

Here's a website where they are only $300...

Remote Ballast Enclosures & Replacement Ballast Kits - Plantlighting Hydroponics & Grow Lights

this ballst will power TWO 600 watt HPS lights...